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(N0 Mode l.) 2 Sheets--Sheet I. 'J. H. STEVENS & M. G. LEFFERTS.

APPARATUS FOR PRODUGING PYROXYLIN SHEETS.

Patented Dec. 29, 1896,

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WITNESSES H m mvemom M 1 W l3 BY MI? MW 5Q W I I ATTORNEY'J {No Model.) 2 Sheets-Sheet 2.

J. H. STEVENS & M. G. LEFFERTS. APPARATUS FOR PRODUGING PYROXYLIN SHEETS.

No. 573,928. Patented Dec. 29, 11896.

' INVENTOH Mi. J

35 and sheets cut from it, either in UNIT-En [STATES-Y,

PATENT O FICE.

J OHNI-L- STEVENS, OF NE WARK, NEW JERSEY,- AND MARSHALL G. JLEFFERTS, OF N YORK, N. Y., ASSIGNORS TO THE CELLULOID COMPANY, OF NElV YORK, N; Y., A 'COR'PORATION OF NEW JERSEY.

APPARATUS; FoR Pnooucl-uoPYRoxYLmsHEsTs.

SPEGIFICATIlON forming part of Letters Patent N 0. 573,928, dated December-29, 1896.

Application filed July '1 7, 1,891,

. To all whom, 1ftnut-il Cont-urn.-

Be it known that we, JOHN H. STEVENS, residing at Newark, in the county of Essex and i State of New Jersey, and MARSHALL G. LEF- l 5 FERTS, residing at New York city, in the county and State of New York, citizens of the 5 United States, haveinvented c'ertainhewand g the 1 Production efiPyroxylin Sheets, of which the useful llnprov ments in Apparatus for 10-. following is a specification.

This invention has for tives or positives.

sheets. r has been dissolved in suitable solvents to a .0 fluid or semifluid condition and then poured or spread upon a smooth surface of glass and l, and afterward stripped i he form of a thin sheet, 5

other method which has? permi ted to d1", from the glassin Accordingto the 2 5 hecn-employedthe pyroxylin has been converted into a solid compound by the use of a comparatively small proportion of solvent its object the pro- ,duction of' long sheets or films of pyroxylin material, usefulfor many purposes in the arts, I

as well as specially applicable to the 1nann- 5 i5 fa'cture of supports for photographic nega-g Heretofore two general! methods have been employed in making such careful washing or In one of these the soluble pyroxylin 2 Swallow-399,832. on model.)

i especially for .the' reason that. the pyroxylin solution could not corrode or otherwise injure the polished surface of the glass." Although pyroxylin solutions had no corrosive cifect upon glass, they wereof such nature that their contact with metal was apt to .corrode or oxidize the polished surface of any except some of the noble metals and so ruin the saidsurface for the purposesherein described.

. \Ve have discovered from our experiments that the corrosive action of ,pyroxylin solutions is due to the free acid left in the-pyroxylin by-imperfect washing or developed in it by decomposition, and we have'ascertained that, 'byusing pyroxyliu in which these acids have'been thoroughly removed by neutralized by means of some mild basic salt or substance (either while the pyroxylin is being washed or even after it has been dissolved) and also by using perfectly neutral solvents the power of corg rod'i-ng or oxidizing the baser metals'ordinarily possessed by .pyroxylin compounds is destroyed, a-nd we are enabled to makea pyroxylin. solution which, when coated upon a metallic surface and dried and stripped therefrom, has exactly the same appearance as and by the aid of masticating operations in I though. madeu'pon glass,twhile the'surface of heated rolls, in which case the stimulating 3e eifect of the heat and pressure enabled the employment of so littlesolvent that the compound from first to lastwas maintained in a solid condition. This solid compound'was molded into a block or other suitable shape planing-machine. V The employment of this latter method has permitted the production 7 of very long sheets; but in the method where thin pyroxylin solutions or compounds. are 40 spread upon a surface of glass and permitted to dry, which method is-very desirable in certainyapplications, the. size or superficialexparted a similar surface to the pyroxylin com 5 pound dried in contact with -it,-but more a lathe or the metal remains practically uninjured; e are thus enabled to-replace the slow an expensive methods heretofore employed,- whercin the pyroxylin material was spread upon glass of limited length, by substituting there v for a metallic surface, by which means we-can obtain sheets in quality of finish or polish equal to those-made upon glass.

. One novel feature of this invention is, therofore,,the substitution of a smooth metallic surface for the surface of glass which has heretofore been used in forming sheets from t fluid pyroxylin, compounds; and as an additionalnovelty of this invention we make such-surface of metal in the form of an endless belt, upon which the pyroxylin solution is spread and dried while the belt is in motion, and then stripped from the 'beltbefore it has made a complete revolution, thus fur;

'nishmg a means for manufacturing uniform sheets with great regularity and rapidity and of practically unlimited length, and the'reflexible, and made, preferably,

. material softer than the surface of the belt or wheel to avoid abrasion,

eovery of the evaporated solvents, heretofore been practically impossible, -this means rendered perfectly practicable, because it permits the adoption of mechanism in which the ordinarymethods of condensation are employed, all as plaiued.

In carrying out this invention an apparatus may be employed substantially as herein specified and as illustrated .in the drawings, in which similar letters indicate similar parts.

Figure 1 is a longitudinal sectional view of our apparatus. Fig. 2 is a plan view of the same. Fig. 3 shows a modification. Figs. 4, 5, and (i show enlarged detail views of hopper H.

The process of this invention forms the subject-matter of another application for Letters .lfatent of the United States filed by us, of even date herewith, Serial No. 399,833.

E 1;, Figs. 1 and 2, is an endless belt of metal of such thickness as tobe strong butof German silver or'nickcl-plated copper,placed around the pulle tion. This belt can be of width and length and canbe supported or prevented from sagging by the use of idlers or other well-known means for supporting it between the pulleys I P. No mechanism for imparting motion to the pulleys 1 P is shown in the drawings. Any suitable mechanical means can be employed to move the pulleys so long as the arrangement permits the rate of speed to be regulated as desired, the rate of speed, aswill be understood, dependiu g upon the consistency or drying properties of the pyroxylin solution, length of belt,

any. convenient and other conditions.

In Fig. 13 a modification of the apparatus is shown bypassing the endless belt'around a large pulley or wheel A or using the surface of such wheel itself.

3 II is a hopper which contains a solution of the pyroxylin compound. It is open at itsbottom at'a point directly over the belt or wheel, and the size of this op'eningca-n be varied as desired by raising or lowering a plate (I within the hopper by means of a handle a.

The thickness of the strip of-the solution which is flowed upon the wheel or belt is varied by means of a scraper h,'which is moved to and from the belt by finger-screws m and is clamped in position by thumbscrews 1. Scraper 7L2 is composed of rigid and is in contact with the belt or wheel, so as to prevent the spread of solution in that direction. Figs. 4, 5, and 6 show enlarged views of hopper 11, with the plate (I and scrapers h and b S R, Figs. 1, 3, and 3, is a stripping-roll for stripping the pyroxylin sheet from-the belt or wheel from whence it passes over the drying-rolls D R.

D R, Figs. 1', 2, and 3, is a series smooth or polished metal, capable of runs of ofbeing ys *II, from which it receives its mo-- friction for the passage which has heated or cooled by suitable steam or water is by pipe attachments 13,

Figs. 2 and 3. These rolls can be replaced by any curved surfaces, such as half-rolls, answering the same end, or cloth'or paper covered rolls can be used is hereinafter exland furnish excellent means for drying.

Provided the half-rolls do not ofier too miich of the film they will do fair work, but the revolving rolls or wheels 5 are preferred.

, a nature that W R, Figs. 1, :2, and 3, is a winding-roll upon which the sheet of dry pyroxylin compound can be wound. This winding-roll may consist of a simple spool. of wood or other-suitable material arranged so that it canbe'detached from the shaft S, carrying with it the pyroxylin sheet P S wound upon it, thus furnishing a convenient core for-the same.

It is sufiicient to say that the pyroxylin must be free from acid, as already described, and that the solvents employed should be neutral and of such rapidly as possible consistent with the desired quality of the resultant film and will leave the pyroxyliu in the form of a smooth'sheet of a homogeneous nature. The solubility of the pyroxylin and the employment of ysolvents in proper proportions to obtain the right consistency and of suitable volatility and freedom from water, and also the use in the mixture of solid solvents, like camphor and colorless ingredients, for transparent effects,

and dyes or pigments or other substances which will modify the character of the dry sheet, are matters well understood by manufacturers of these compounds. The skilled operators in this art are acquainted with'the requirements of pyrokylin solvents and the diiferenteffects produced in using solvents of varying characteristics, and therefore it is suflicieut to state that among the solvents described in United States Lettrslatent Nos.

- 209,340, 269,31t1, 269,342, 2695343, 269,344,":nid

269,345, issued onfDecember 19, 1882, to the Celluloid Manufacturing Company, on the ap-.

plications of one of us, will be found substances. possessing the requisite properties useful for the purposes of this patent.

In operating the apparatus the endless belt E B or the wheel ings, and the hopper II, kept filled with the pyrox'ylin solution by any suitable .means,

to become set or too stiff to flow before ithas left the horizontal position and begun to pass over the first pulley to which it comes. The

Pyroxylin compounds suitable for the formation of sheets by evaporation are-too well known to require description.

If a .belt' the solvent will evaporate as IIO A is set in motion in the di-, rection indicated by the arrows in the draw-- employment of the wheel is limited dresses 4 where the solvents are sufiicie'ntly volatile to 2 4 nearest pulley or the wheel. This prevents permit the spreading solution to s'et quickly,

. so thatthe absence of horizontal positions will notcause irregularities in the dried sheet bythe flowing of the solution or compound,

The speed of the belt or wheel, and also the I flow from the hopper, should be so regulated that the sheet will have become sufficiently dry tobe stripped and ;-pass'ed over the dry- ,ing-rollsflbefore it has made a complete revo-,

a This stripping-roll performs the very imporlution with the belt or'wheel and before'the portion of the belt towhlch it adheres reaches thehopper. i

In regard'tothe strlppihg-rollS R we would state that it ought-to -he of," small diameter,

preferably about eight inches in diameter",-

of straight face andsmooth surface, and to be parallel with the face of thebelt or wheel.

. wheel, so that-the filin' will be stripped immeor at the first pointof contact therewith, and

- o manner that the freshly-stripped'sheet is face ofthe wheelor belt.

diatelyafter passing under the strippingrroll,

on a line with thecenters of the roll and the stretching or distorting the film by reaso ofits tendency to' leav'e,the wheel or beltirregularly and not on a line parallel with the This strippingroll is preferably arranged so as torcvolve with the stripped film, but this is notabsolntely' necessary in order to keep the sheet straight, because it would perform the same. function if fixed,'but with more friction and danger of stretchingthe film. ,In the latter case any curved s'urfaze ld answer in place brought successively in contact with rolls of constantlyincreasing temperature the-residues of volatile solvent are driven oif very.

apidly,and great economy in time is thus efiected, and the capacity of the driving'belt 'orwheel is also, greatly increased, for it has been found that by maintaining a tension upon the sheets while they are in contact with heated rolls the evaporation of the sol-' vent from the compound on the endless belt or wheel need only to be carried to a point I where the solution willihave becomeset in the condition of a nitiderately soft sheet,

which can then be; stripped andpassed over .Lne drying-rolls. In all cases it is preferable the spool-orwinding-roll W R. The last one or more drying-rolls over which the-sheet passes are preferably of a lower temperature than the others, in order to chill the sheet be-' fore it is reeled upon' the windingsroll W R;

In using cloth-covered rolls the drying may be done in the air at ordinary temperatures.

or in specially dry or slightly-heated air..

\Vhilc we have described and shown a prc- :ferred form of apparatus, yet we desire it to be understood that this apparatus may be greatly varied and departedfrom without be-. ing outside the limits of our invention. For instance, instead of using one or more drying-rolls any other drying surface or surfaces maybe used, preferably differing from each other in temperature, or a single surface may be used and parts of it vary; from each other in temperature. Many other changes may suggest themselves to persons availing'themselves of our invention and these be within theseope of our improvements. I

Of course it is obvious that by using a very rapid drying solution on a very large .wheel or extra long belt moving at a very slow rate 'of speed a film would be formed sufficiently dry to beused fora'greatmany practical pun poses, thus obviating the necessity forfidry' ing rolls, but we donot prefer such a method inview-of the excellent results produced by our preferred process. I

When a polished sheet is required, the metal /belt or,wheel willalso be polished on the side which comes in contact with the sheet,-or, if the design is not too rough or deep, the metal surface can be given any character desired, which will be in turn imparted to the pyroxylin "sheet with which it comes in contact. 'lhisapparatus can be connected with a suit,- able condensing apparatus for recovering the evaporated solvents by simply inclosingthe endless beltbr wheel whollytor partially in or permitting it to pass through a chamber containing chilled surfaces, with suitable means for carrying off the condensed solvents.

Such chilled surfaces can be produced by freezing mixtures or by the expansion of gases, as is well understood. Suitable means for maintaining an elevated temperature in the film will in such case be preferable, and

in fact thewheel or belt surface should in all cases be maintained at a temperature of at least, to counteract the chilling effect 0 evaporating liquids. This can be done b internal heating or any appropriate means.

The surface of the belt or wheel may boo any materialsother than metal, such as glasmv .or hard rubber, for instance, applied by a suitable means, which are capable of present-,

ing a smooth highly-finished surface, and if the well-known difliculties in applying such surfaces are overcome and the surfaces be such that acidsQwill notcorrode them it not-of course be necessary to be so carefulm freeing thepyroxylin from acids, but metal surfaces and carefully prepared pyroxylin are the best conditions for" successful work.

It is of course obvious that there is a limit to the thickness of sheets produced by this method and that heavy or thick sheets are practically excluded. Thin or fairly thin sheets are those contemplated, or such sheets as are usually made by evaporating. down flowable pyroxylin solutions on surfaces.

The use of heat to produce fluidity in-the solutions or the heating or cooling of any por- 3 tion of the belt, pulley, or other mechanism employed for the purpose of modifying the evaporation or for other effects may be employed with the operation of this device.

By means of the herein-described median economy than has heretofore been possible with sheets of limited superficial measurement made by evaporating vpyroxylin compound', on glass. These sheets can be used for all purposes to which other thin pyroxylin sheets have been heretofore applied, and they are specially applicable to photographic purposes, such as photographie-negative sup ports when transparent or semitransparent, and fofphotographic positives when suitably combined with pigments.

I We are also aware that benzin and benzol and other hydrocarbons obtained from coal and petroleum have been employed in conjunction with such pyroxylin' solvents as are capable of holding them in solution, for Alexander Rollason in English Patent No. 2,849 of R58 and Henry Iarkes in English Patent No. 1,866 of 1879 described such use of these naphthas, and we include the use of such sub: stances in our process. I We are also aware that the term pyroxy- Iin compound includes all mixtures, plastic or non-plastic, liquid, semiliquid, or solid,

consisting of pyroxylin dissolved lb or settened by or combined with solvents OPOthGI materials.

What we claim, and desire to secure by Let tors Patent, is-

1'. In a machine for making sheets or strips of pyroxylin compound, an endless carrier, a

ho- )er, means for rc ulatin the rate and,

quantity of fiow of a solution of pyroxylin means for confining the'flow of the" solution toward the scrape r,su bstant-iall y as described. In testimony whereofwe aflix oursignat ares, in presence of two witnesses, this 7th day of July, 1891, 

